This invention relates to the field of hearing aids, and more particularly to accoustic seals for use with the sound transmitting tube from a modular "In The Ear" hearing aid which is directed into the ear canal.
My prior patent, U.S. Pat. No. 3,934,100, pertains to an acoustic coupling seal for use as an ear tip for insertion within the ear canal. In my prior invention, the tip has a plurality of openings along the axis to form ribbed portions substantially parallel to the axis of the housing, and also includes a disc with a plurality of apertures to permit a direct flow of sound from an external source through the apertures and the openings in the tip to the ear. Because that prior tip permitted sound delivered through the sound tube to escape through the plurality of vent apertures in the disc, a possible problem preventing use of that ear tip for "In The Ear" hearing aids arose through feedback of sound energy from the sound tube through the vent apertures to the microphone of the "In The Ear" type hearing aid.
In another known "In The Ear" hearing aid, a vent tube is provided and cast in the custom molded ear mold. In this type of hearing aid, the venting is provided at a fixed location which may not always be suitable for various wearers of the aid. In other known custom molded hearing aid units, the venting is similarly restricted, and no quickly assembled ear tip coupler can be used as a temporary vented earpiece until a custom ear molded unit has been cast.